The present invention generally relates to an image processing apparatus arranged such that the outline of a figure is represented with outline vectors, and can be created from the outline vectors upon painting out the internal region of the outline.
Conventionally, a seed filling method or a scan filling method is known as a method of painting out an optional region of the figure. Although the seed filling method is adopted in many image processors, it has a defect in that the processing speed is slower a comparison to the scan filling method. In the scan filling method, it is so arranged that the outline of the figure to be painted out as shown in FIG. 11, for example, is shown with the outline vectors, and the figure is adapted to be painted out when the directions of the outline vectors are painted out on the left side thereof. The outline vectors shown in FIG. 12 (b) are created from the initial data shown in, for example, FIG. 12(a). Such an outline as shown in FIG. 13(a) is created from the outline vectors of FIG. 12(b). In the scanning operation in the x direction, the painting-out operation starts at odd-numbered intersections between the horizontal scanning lines and the outline. Subsequently, the painting-out operation is stopped at the even-numbered intersections, and thereby results in such a figure as shown in FIG. 13( b).
An image processing apparatus, arranged such that the figure is painted out by such a scan filling method as described hereinabove, is conventionally disclosed in Japanese Pat. Publication Tokkosho No. 53-41017. The image processing apparatus creates the outline in accordance with the known Bresenham algorithm from the outline vectors, and, for example, the outlines as shown in FIG. 14(a), FIG. 15(a), and FIG. 16(a) are provided.
In the scanning operation in the x direction, the painting-out operation starts in the odd-numbered intersections between the horizontal scanning lines and the outlines, with the intersected picture elements being painted out. The painting-out operation is stopped at the even-numbered intersections, with the painting-out operation being effected so far as the intersected picture elements.
In case of creating the outline by the conventional image processing apparatus, the position of the picture element becomes the outline when the outline vectors overlaps on the same picture element as at the top portion in FIG. 14(a) and at the central portion in FIG. 15(a). When the horizontal scanning line is intersected by the outline, all the picture elements on the right side thereof including the picture element, are painted out. Thus painting out errors as shown in FIG. 14(b) and FIG. 15(b), are caused. If the outline ends in the odd-numbered picture element, counted from the initial picture element the scanning line intersects when the outline parallel to the scan direction is created, as shown in FIG. 16(a), the picture element on the right side of the odd-numbered picture element is painted out. This causes such painting out errors as shown in FIG. 16(b).
In order to prevent such errors from being caused, the processing operation is effected such that the position of the picture element deviated by one dot in the x-axial direction from the outline of the top portion may be outlined as shown in, for example, FIG. 13(a). In the outline parallel to the scanning direction, the processing operation is effected such that the length may become an even-number dots or only a start point and an end paint are plotted. In this case, the processing speed of a host effecting the processing operating becomes slower, with the load of the host becoming larger. When the outline is contracted or rotated, with the outline obtained through the processing operation effected on the vector font being stored in a mask ROM, etc., for example, when the outline shown in FIG. 17(a) is contracted with that shown in FIG. 17(b), such painting out errors as described hereinabove, may be caused. When the processing is effected for the outline shown in FIG. 18(a), the outline becomes that such as one shown in FIG. 18(b). When it is painted out, the outline becomes one such as that shown in FIG. 18(c), so that a figure of a different shape is created from the figure shown in FIG. 18(a).
The outline, wherein errors are caused or shapes are made different when such a painting-out operation has been effected, as shown, as a typical example, in FIG. 19. The outlines shown in FIG. 19(a) and 19(b) are the same as those shown in FIG. 14(a) and FIG. 16(a). FIG. 19(c) shows a case, wherein two boundaries share the same picture element. FIG. 19(d) shows a case, wherein two boundaries are in complete conformity with each other as a limit of FIG. 19(c). The outline surrounded by a circle mark shows one, which causes the error.
In the conventional image processing apparatus, to produce such outline as shown in FIG. 19 during the outline creation, it is necessary to effect such a processing operation upon the outline for preventing the errors from being caused during the figure painting-out operation, with a problem being caused of the processing speed becoming slower. In order to apply the processing, the figure shape after the painting out becomes considerably different from the initial figure, thus being more variable in magnification than the dot font, and a problem is caused that the characteristics of the vector font, with the rotation being easier and the font being beautiful, and cannot be sufficiently used.